Powerfold actuator for exterior mirror

ABSTRACT

A vehicular exterior rearview mirror assembly includes a powerfold actuator electrically operable to pivot a mirror head relative to a mounting base. The actuator includes a biasing element disposed between an upper housing and an upper end of a pivot tube and releasably retains the powerfold actuator in at least one detent state. An upper detent is disposed radially outboard of the pivot tube and radially inboard of an output gear and a lower detent, and the upper detent includes a detent lip that engages an upper detent surface of the lower detent. When the actuator is in a primary detent state, a spring load path of the biasing element is through the output gear and lower detent to the base. When the actuator is in a secondary detent state, the spring load path is through the detent lip of the upper detent and lower detent to the base.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims the filing benefits of U.S. provisionalapplication Ser. No. 63/106,421, filed Oct. 28, 2020, which is herebyincorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to the field of exteriorrearview mirror assemblies for vehicles and, more particularly, to thefield of powerfold exterior rearview mirror assemblies.

BACKGROUND OF THE INVENTION

It is known to provide an automotive exterior rearview mirror assemblythat includes a foldable mirror assembly, such as a powerfold mirrorwhere the mirror head is pivotable via an actuator between a drive oruse position and a folded or park position.

SUMMARY OF THE INVENTION

A rearview mirror assembly (such as an exterior mirror assembly mountedat a side of an equipped vehicle) includes a powerfold actuator systemthat pivots the mirror head of the mirror assembly between a drive oruse position and a folded or park position, such as responsive to a userinput. The powerfold actuator may include a pair of drive motors andthus may provide enhanced or greater output torque, such that theactuator is suitable for large SUV or pickup truck exterior mirrorapplications, and may be suitable for larger trailer tow mirrorapplications. The powerfold actuator includes a primary detent assemblythat functions to retain the mirror head at the drive position or parkposition, and also includes a separate secondary detent assembly thatfunctions to retain the mirror head at the drive position when themirror head, after powered folding to the folded position, is manuallypivoted from the folded position to the drive position. During operationof the powerfold actuator, the actuator functions to lift the mirrorhead relative to the mounting base (at the vehicle) so that there arereduced forces and reduced friction at the cut line seal that isdisposed between the mirror head and the mounting base.

These and other objects, advantages, purposes and features of thepresent invention will become apparent upon review of the followingspecification in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front plan view of an exterior rearview mirror assemblypivotally attached at a mounting base at a side of a vehicle;

FIG. 2 is a top plan view of the exterior mirror assembly, with themirror head pivoted to a drive or use position;

FIG. 3 is a top plan view of the exterior mirror assembly, with themirror head pivoted to a folded or non-use position;

FIGS. 4 and 5 are views of a powerfold actuator of the exterior mirrorassembly of FIGS. 1-3 ;

FIG. 6 is an exploded view of the powerfold actuator;

FIG. 7 is an upper perspective view of the powerfold actuator;

FIG. 8 is a side elevation of the powerfold actuator of FIG. 7 ;

FIG. 9 is a sectional view of the powerfold actuator of FIG. 7 , shownwith the upper detent removed;

FIG. 10 is a perspective and partial sectional view of the powerfoldactuator, showing the load path of the biasing force when the actuatoris in its primary detent position;

FIG. 11 is a top plan view of a portion of the powerfold actuator ofFIG. 10 ;

FIG. 12 is a side view of the powerfold actuator of FIG. 10 ;

FIG. 13 is another side view of the powerfold actuator of FIG. 10 ;

FIG. 14 is another perspective and partial sectional view of thepowerfold actuator, showing the load path of the biasing force when thepowerfold actuator is in its secondary detent position;

FIG. 15 is a top plan view of a portion of the powerfold actuator ofFIG. 14 ;

FIG. 16 is a side view of the powerfold actuator of FIG. 14 ;

FIG. 17 is another side view of the powerfold actuator of FIG. 14 ;

FIG. 18 is another side view of the powerfold actuator, shown when themirror head has been manually pivoted;

FIG. 19 is a block diagram showing operation of the powerfold actuatorafter the mirror head is electrically folded rearward from the driveposition when in the primary detent state to the park position and thenmanually folded forward so as to be back in the drive position but inthe secondary detent state;

FIG. 20 is a block diagram showing operation of the powerfold actuatorafter the mirror head is manually folded forward from the drive positionwhen in the primary detent state;

FIG. 21 is a block diagram showing operation of the powerfold actuatorafter the mirror head is manually folded rearward from the driveposition when in the primary detent state;

FIG. 22 is a top plan view of the powerfold actuator, showing exemplarydimensions; and

FIG. 23 is a side elevation of the powerfold actuator, showing exemplarydimensions.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings and the illustrative embodiments depictedtherein, an exterior rearview mirror assembly 10 for a vehicle 11includes a mirror head 12 that includes a mirror reflective element 14received in and/or supported at or by a mirror shell or casing 16 of themirror head portion 12 (FIG. 1 ). The mirror head portion 12 includes amounting portion 12 a that is pivotally or movably mounted to a mountingarm or base or portion 18. The mirror assembly 10 comprises a powerfoldmirror (where the mirror head portion may be pivoted via an actuatorassembly or adjustment device), and may comprise a breakaway mirror(where the mirror head portion may be manually pivoted about themounting arm or base). The mounting arm or base 18 of mirror assembly 10is mounted at the side 11 a of a host or subject vehicle 11 equippedwith the mirror assembly 10, with the reflective element 14 providing arearward field of view along the respective side of the vehicle to thedriver of the vehicle, as discussed below.

The powerfold mirror assembly 10 includes an actuator 20 that isoperable to pivot the mirror head 12 (comprising the mirror casing 16and reflective element 14) relative to the mounting arm or base 18. Theactuator 20 operates, such as responsive to a user input, to pivot themirror head 12 between a plurality of detent positions, including a useor drive position (FIG. 2 ) and a folded or park position (FIG. 3 ). Themirror head is also pivotable manually to either the use or foldedposition. The actuator may pivot the mirror head 12 between the driveposition and the folded position responsive to the user input, or theactuator may pivot the mirror head automatically, such as uponcompletion of performance of a parking maneuver of the vehicle or uponlocking or unlocking of the doors of the vehicle.

When in the use or drive position, the mirror head 12 is extended fromthe side of the vehicle so as to provide the rearward field of viewalong the side of the vehicle to the driver of the vehicle. When in thefolded or park position, the mirror head 12 is folded or pivoted orrotated from the extended position toward the side of the vehicle, suchthat the mirror reflective element 14 may be facing the side of thevehicle and does not provide the rearward field of view along the sideof the vehicle. Optionally, the mirror head may also be pivoted to afully forward position, where the mirror head 12 is folded or pivoted orrotated away from the folded position and beyond the use position, suchthat the mirror reflective element 14 may face sideward or forward awayfrom the vehicle. The mirror head 12 may pivot toward the fully forwardposition manually, such as upon contact or a collision with an object. Aseal may be disposed along the interface between the mounting portion 12a of the mirror head 12 and the mounting arm or base 18, such as toreduce noise or damage from vibration of the mirror head 12 relative tothe mounting base 18 and/or to preclude moisture or debris from enteringthe mirror head 12 or mounting base 18. The actuator may utilize aspectsof the actuators described in U.S. Pat. Nos. 7,887,202 and/or 9,487,142,and/or International Publication No. WO 2019/035078, and/or U.S.Publication No. US-2021-0261053, which are all hereby incorporatedherein by reference in their entireties.

As shown in FIGS. 4-9 , the mirror actuator 20 comprises a pivotassembly that has a base post construction that is fixedly disposed ator attached at the mounting base 18 and that has a pivot tube or post 22and a base 21 integrated together (or that has a separate base and pivotpost joined together) with the pivot post 22 providing or defining apivot axis for the mirror head 12. The post 22 extends from the base 21and extends through a lower detent plate 24 and an output gear 26 thatare disposed at the post 22 and that are keyed together andnon-rotatable relative to one another but rotatable relative to the post22 and the base 21 when the mirror head 12 is manually pivoted, asdiscussed below.

An actuator housing or bracket (comprising a lower housing 28 and anupper housing 30) is rotatably disposed at the post 22 and houses a pairof motors 32. The actuator housing is non-rotatably disposed or attachedat the mirror head 12 so that movement or rotation of the actuatorhousing about the pivot axis of the pivot post 22 translates to movementor rotation of the mirror head 12. Thus, the motors 32 are actuated topivot or rotate the actuator housing, and therefore mirror head 12,about the pivot axis. The motors 32 are actuated to rotatably drive arespective motor worm gear 32 a that rotatably drives a respective maingear 32 b, which engages the output gear 26 and rotates the housingrelative to the output gear 26 until a hard stop is engaged, whereby themotor will stall or stop, with the mirror head 12 retained at theextended or drive position via detent elements or engagements or statesof the actuator. The actuator 20 is configured such that a hard stop isprovided at the appropriate locations when the mirror head 12 is pivotedvia driving of the motor to position the mirror head as desired, such asat the folded position and at the use position.

The post 22 extends from the base 21 and through the lower detent 24 andthe output gear 26. The lower detent may be disposed between the lowerhousing 28 and the base 21 and engage the output gear 26 through anaperture of the lower housing 28. The post 22 further extends through anupper detent element 34 and an output gear bushing 36, with the outputgear bushing 36 disposed between the output gear 26 and the upperhousing 30. The upper housing portion 30 attaches to the lower housing28 and encloses a portion of the post 22, the motors 32 and worm gears32 a and main gears 32 b, the upper detent element 34, the output gear26, the output gear bushing 36, and at least a portion of the lowerdetent 24. A retainer 38 is rigidly fastened to the post 22 orintegrally formed as a flared end of the post (as shown in FIGS. 7-9 ),such that the retainer 38, post 22 and base 21 are effectively a singlemember or element and provide axial and rotational ground reference forall motions and forces. A spring or biasing element 40 is disposedbetween the retainer 38 and an upper surface of the upper housing 30 andurges or biases the actuator housing downward toward the output gear 26and base 21. The spring 40 (or other suitable biasing or urging element)provides the primary load and exerts a downward force at the upperhousing 30, to bias the actuator housing toward the lower detent 24 andthe base 21, so that the actuator housing engages the base 21, via theoutput gear 26 and detent plate 24, during electric folding.

The output gear 26 and the lower detent plate 24 are keyed together anddo not rotate or move relative to one another. The output gear 26 andlower detent 24 do not rotate relative to the post 22 during electricactuation of the actuator 20 via operation of the motors 32. The upperdetent 34 is non-rotatably keyed or rotationally locked relative to thebase 21 and the post 22 such that the upper detent 34 is non-rotatablerelative to the post 22, but can move axially along the post. The upperand lower housing portions 28, 30 are attached to one another and pivotaround the post 22 and are urged toward engagement with the upper detent34 or output gear bushing 26 via the spring 40, as discussed below.

As can be seen with reference to FIGS. 10-18 , the upper detent 34 isdisposed radially inward of the output gear 26 and has an upper detentlip 34 a that extends radially outward and engages an upper end 24 a ofthe detent plate 24, with the upper detent lip 34 a and the upper end 24a of the detent plate 24 being correspondingly formed with ramps toallow for pivotal and axial movement of the upper detent 34 relative tothe detent plate 24. Thus, the upper end 24 a of the detent plate 24 andthe upper detent lip 34 a of the upper detent 34 form a detentinterface, where, when the ramps of the upper end 24 a and the upperdetent lip 34 a are engaged and travel along one another (i.e., thedetent plate and the upper detent rotate relative to one another), thedetent plate 24 and upper detent 34 move axially along the pivot post 22according to the engagement of the ramps. Similarly, the lower end 24 bof the detent plate and the upper end 21 a of the base 21 (see FIG. 13 )are correspondingly formed with ramps to allow for pivotal and axialmovement of the detent plate 24 relative to the base 21 when the mirrorhead is manually pivoted.

Thus, the detent plate 24 may move axially along the pivot post 22relative to the base 21 according to the engagement of the ramps of thelower end 24 b of the detent plate and the upper end 21 a of the basewhen the detent plate 24 pivots relative to the base 21. The insideupper surface of the upper housing 30 may also have ramps/recesses thatcorrespond with ramps/protrusions at the upper end of the upper detent34 and thus the upper housing 30 and upper detent 34 may move axiallyrelative to one another when one or both are pivoted, according to theengagement of the ramps of the inside upper surface of the upper housing30 and the upper end of the upper detent 34. When the housing isassembled, the output gear 26 and output gear bushing 36 are housedpartially within and between the upper housing 30 and lower housing 28,with the lower end 26 a of the output gear 26 non-rotatably keyed tostructure 24 c at the detent plate 24, which allows for the output gearto move axially relative to the detent plate 24.

Thus, during operation, the actuator 20 is typically in the primarydetent state (FIGS. 10-13 ), where the lower end 24 b of the detentplate 24 is meshed or nested with the upper end 21 a of the base 21 andwith the upper end 24 a of the detent plate 24 meshed or nested with theupper lip 34 a of the upper detent 34 (see FIG. 12 ). The loading forces(exerted by the spring) thus are through the housing, the output gearbushing 36, the output gear 26 and the detent plate 24 to the base 21,with the upper detent 34 effectively floating within the actuator 20.During operation of the actuator 20 when in the primary detent state,the motors 32 drive the gears to move or pivot the mirror head (viarotating the housing about the output gear) about the pivot axis of thepivot tube 22, while the output gear 26 remains fixed at the pivot tube22. As the housing and mirror head 12 are rotated from the use positiontoward the folded or park position, the housing lifts in relation to thebase 21 while turning, and such lifting lifts the mirror head andincreases the gap between the mirror head mounting portion 12 a and themounting base 18 and thus reduces or limits or avoids pressure at thecut line seal (the seal that is disposed between and at the interface ofthe mirror head mounting portion 12 a and the mounting base 18 and thatfollows the contour and fills the gap between the mirror head 12 and thebase 18) during pivotal movement of the mirror head 12.

When the mirror head 12 is manually pivoted (such as from a parkposition where the mirror actuator is in the primary detent state to aforward folded position), the actuator 20 can be set to the secondarydetent state (FIGS. 14-17 ). As the mirror head 12 is manually pivotedfrom a position when in the primary detent state, the lower housingportion 28 and the output gear 26 are rotated while both the upperinterface between the upper end 24 a of the detent plate 24 and the lip34 a of the upper detent 34 is disengaged and the lower interfacebetween the detent plate 24 and the base 21 is disengaged (see FIG. 18). During such manual pivoting of the mirror head 12, the mirror head 12and actuator housing and output gear 26 and detent plate 24 all rotatetogether and in tandem about the pivot tube 22 relative to the base 21(which is fixedly attached at the mirror mounting base or arm),resulting in the detent plate 24 rising upward along the ramps at thedetent plate-base interface, which also raises the upper detent 34 intoengagement with the upper housing 30 when the mirror head 12 arrives atthe new (e.g., forward folded) position. The loading forces (exerted bythe spring) that retain the mirror head in the new location ororientation thus are through the actuator housing, the upper detent 34and the detent plate 24 to the base 21 when the actuator 20 is in thesecondary detent state.

As shown in FIGS. 19-21 , the actuator 20 operates to return the stateof the actuator to the primary detent state when the mirror head ismanually pivoted to the secondary detent state. In other words, when themirror head is manually pivoted, such as from the folded position to thedrive position, the actuator is in the secondary detent state. When theactuator is in the secondary detent state, operation of the actuator mayreturn the actuator to the primary detent state. FIGS. 19-21 show thedifferent processes that return the mirror actuator to the primarydetent state after the mirror head is pivoted from an initial position(in the primary detent state) to a new position forward or rearward ofthe initial position. For example, when the secondary detent retains themirror head in the drive position (such as after manually folding themirror head forward from the park position), subsequent powerfolding ofthe mirror head to the folded position and back to the drive positionwill cause the mirror head to be retained by the primary detent (seeFIG. 19 ).

Thus, the mirror actuator has a double detent feature with an upperdetent that is disposed radially inward of the output gear and the baseplate. While this may reduce the pivot tube size, the pivot tube isdimensioned to provide sufficient strength for the actuator. Optionally,the diameter of the pivot tube may be increased, such as to provideadded strength or to provide a passageway through the pivot tube, suchas for electrical connectors or wiring for the exterior rearview mirrorassembly. Although shown and described as having two motors thatrotatably drive gears that engage different portions of the output gear,it is envisioned that aspects of the actuator are suitable to andapplicable to a single motor actuator. In the illustrated embodiment,the motors are oriented vertically, with their output shafts and wormgears arranged vertically (parallel to the pivot axis of the pivottube), which provides a dual motor actuator with a smaller profile orfootprint compared to other dual motor actuators with the motorsarranged horizontally.

Exterior mirror heads are getting larger, with more mass and wind loadthan the current actuators may be designed for, and the exterior mirrorheads have more electronic content, requiring larger wire harness andmore electrical connectors to feed through the pivot tube. The mirroractuator has a sufficiently large passageway through and along the pivottube for the wire harness, while also providing for double detentcapability, which allows the exterior mirror head to always be in adetent state when in the drive position (thus maintaining the springload through the actuator to maintain the mirror head in the driveposition).

The actuator provides a powerfold feature for large trailer tow mirrorapplications that feature two motors, two gears and three stop pins. Theactuator provides higher output torque and increased vibration stabilityand has higher self-locking in the drive position compared toconventional actuators. The actuator provides a heavy duty design forlarge SUVs and pickup truck applications, and may provide for a foldingfunction for large extendable trailer-tow mirrors. The actuator mayinclude an external shut off device.

The powerfold actuator thus has enhanced performance and capability(reduced noise, higher torque, lift and turn, double detent, and alarger pivot post hole), having two motors and a double detent functionwith two detent interfaces that become active at different times betweenprimary and secondary detent states. In the primary detent state, theload path as exerted by the spring is through the housing, the outputgear, the detent plate and the base, with the upper detent effectivelyfloating and not engaged by the upper housing. In the secondary detentstate, the load path as exerted by the spring is through the housing,the upper detent, the detent plate and the base, with the output geareffectively floating and not engaged by the upper housing. When themirror head is manually rotated, the main or output gear and platerotate relative to the rotationally fixed upper detent, which causesupper detent to rise into engagement with upper housing. Thus, when inthe primary detent state, the load goes through the output gear, butwhen in the secondary detent state, the load goes through the upperdetent.

The actuator thus provides detents to retain the mirror head at the useposition or at the folded position. When the mirror head is in the driveposition and in the primary detent state, a part of the upper detentsurface of the detent plate is disposed at a correspondingly formedfirst recessed portion of the upper lip of the upper detent, while apart of the lower detent plate is received in a correspondingly formedrecessed portion of an upper detent surface of the base. The secondarydetent functions when the mirror is electrically folded into the parkposition and then manually folded back to the drive position. While boththe upper and lower detents are active in the primary detent function(during powerfolding of the mirror head), only the lower detentinterface is active in the secondary detent function. To return to theprimary detent, the motors are operated to rotate the housing about theoutput gear until the upper end of the detent plate meshes or interfaceswith the upper lip of the upper detent.

Thus, the mirror powerfold actuator has a secondary detent that engageswhen the primary detent disengages. The secondary detent is thus aseparate and distinct detent from the primary detent. A single spring orbiasing element or urging element provides the forces to retain therespective detents in place.

The actuator also provides relief at the cut line seal during pivotingof the mirror head. The coil spring applies load through the upperdetent part, the output gear, and the lower housing when the mirror headis in the drive position (and retained there via the primary detent).When the mirror head is in the drive position, the housing is at a lowerposition and the cut line seal is compressed between the mirror headmounting portion and the mounting base. As the mirror head is pivotedtoward the folded position, the housing lifts away from the cut lineseal to increase the gap and to release pressure at the cut line seal.The mirror head thus lifts slightly to release pressure at the seal, sothere are reduced forces at the seal during pivotal movement of mirrorhead.

Thus, the powerfold actuator provides a double detent featureincorporated with a double or two-motor powerfold actuator. The doubledetent feature is configured to be compatible with an increased diameterpivot tube, such as to provide added strength to the actuator assemblyor to provide a passageway through the pivot tube. The double detentfeature may be accomplished by adding only one additional part ascompared to traditional actuators. The double detent feature can becompatible with other actuator configurations, such as an actuator withone motor or an actuator with a reduced diameter pivot tube.

Changes and modifications in the specifically described embodiments maybe carried out without departing from the principles of the presentinvention, which is intended to be limited only by the scope of theappended claims as interpreted according to the principles of patentlaw.

The invention claimed is:
 1. An exterior rearview mirror assembly for avehicle, the exterior rearview mirror assembly comprising: a mirror headcomprising a mirror reflective element; a mounting base configured forattachment at a side of a vehicle; wherein the mirror head is movablerelative to the mounting base between at least an extended position,where the mirror head is extended outward from the side of the vehicleso that the mirror reflective element is positioned to provide arearward view at the side of the vehicle to a driver of the vehicle, anda folded position, where the mirror head is moved inward from theextended position toward the side of the vehicle; a powerfold actuatorelectrically operated to move the mirror head relative to the mountingbase between the folded position and the extended position; wherein thepowerfold actuator comprises a base portion that attaches at themounting base and a pivot tube extending from the base portion, andwherein the pivot tube extends through a lower detent of the powerfoldactuator, an output gear of the powerfold actuator, an upper detent ofthe powerfold actuator, and a housing of the powerfold actuator, thehousing comprising an upper housing portion and a lower housing portion;wherein the powerfold actuator comprises a biasing element disposedbetween the upper housing portion and an upper end of the pivot tube,the biasing element releasably retains the powerfold actuator in atleast one detent state of the powerfold actuator; wherein the mirrorhead is attached at the housing of the powerfold actuator, and whereinthe mirror head and the housing of the powerfold actuator, when thepowerfold actuator is electrically operated, move together and in tandemabout a pivot axis of the pivot tube of the powerfold actuator; whereinthe powerfold actuator comprises at least one electrically powered motordisposed in the housing, and wherein the at least one electricallypowered motor, when electrically powered, rotatably drives a gear thatengages the output gear to impart movement of the housing and the mirrorhead relative to the output gear; wherein the upper detent is disposedradially outboard of the pivot tube and radially inboard of the outputgear and the lower detent, and wherein the upper detent includes adetent lip that engages an upper detent surface of the lower detent;wherein the upper detent is axially movable along the pivot axis of thepivot tube and non-rotatably engaged with the base portion; wherein theoutput gear is non-rotatably engaged with the lower detent and isaxially movable along the pivot axis of the pivot tube; wherein the atleast one detent state of the powerfold actuator comprises (i) a primarydetent state and (ii) a secondary detent state; wherein the primarydetent state is engaged to maintain the mirror head at the extendedposition when the mirror head is moved via the powerfold actuator to theextended position; wherein, when the powerfold actuator is in theprimary detent state, a spring load path of the biasing element isthrough the output gear and the lower detent to the base portion;wherein, when the powerfold actuator is in the secondary detent state,the spring load path of the biasing element is through the detent lip ofthe upper detent and the lower detent to the base portion; and wherein,with the mirror head in the folded position, and when the mirror head ismanually moved from the folded position to the extended position, theprimary detent state is disengaged and the secondary detent state isengaged to releasably retain the mirror head at the extended position.2. The exterior rearview mirror assembly of claim 1, wherein the detentlip of the upper detent has a lower detent surface that engages theupper detent surface of the lower detent, and wherein the detent lipincludes an upper detent surface that engages an inner detent surface ofthe upper housing portion.
 3. The exterior rearview mirror assembly ofclaim 2, wherein, when the powerfold actuator is in the primary detentstate, the upper detent surface of the detent lip of the upper detentdoes not engage the inner detent surface of the upper housing portion.4. The exterior rearview mirror assembly of claim 2, wherein, when thepowerfold actuator is in the secondary detent state, the upper detentsurface of the lower detent urges the upper detent upward against theinner detent surface of the upper housing portion.
 5. The exteriorrearview mirror assembly of claim 1, wherein, when the mirror head ismanually moved, the output gear and the housing move together relativeto the base portion.
 6. The exterior rearview mirror assembly of claim5, wherein, when the mirror head is manually moved, the housing and theoutput gear move axially along the pivot axis of the pivot tube relativeto the base portion and the upper detent moves axially along the pivotaxis of the pivot tube relative to the lower detent.
 7. The exteriorrearview mirror assembly of claim 1, wherein the at least oneelectrically powered motor comprises two electrically powered motors. 8.The exterior rearview mirror assembly of claim 1, wherein the at leastone electrically powered motor is oriented with an output shaft of theat least one electrically powered motor parallel to the pivot axis ofthe pivot tube.
 9. The exterior rearview mirror assembly of claim 8,wherein the at least one electrically powered motor comprises twoelectrically powered motors that are oriented with the output shaftsparallel to the pivot axis of the pivot tube.
 10. The exterior rearviewmirror assembly of claim 1, comprising a seal disposed between themirror head and the mounting base.
 11. The exterior rearview mirrorassembly of claim 1, wherein, when the mirror head is moved from theextended position toward the folded position, the housing of thepowerfold actuator and the mirror head move axially along the pivot axisof the pivot tube away from the mounting base and the base portion ofthe powerfold actuator.
 12. The exterior rearview mirror assembly ofclaim 1, wherein the biasing element applies a force at the upperhousing from the upper end of the pivot tube.
 13. An exterior rearviewmirror assembly for a vehicle, the exterior rearview mirror assemblycomprising: a mirror head comprising a mirror reflective element; amounting base configured for attachment at a side of a vehicle; whereinthe mirror head is movable relative to the mounting base between atleast an extended position, where the mirror head is extended outwardfrom the side of the vehicle so that the mirror reflective element ispositioned to provide a rearward view at the side of the vehicle to adriver of the vehicle, and a folded position, where the mirror head ismoved inward from the extended position toward the side of the vehicle;a powerfold actuator electrically operated to move the mirror headrelative to the mounting base between the folded position and theextended position; wherein the powerfold actuator comprises a baseportion that attaches at the mounting base and a pivot tube extendingfrom the base portion, and wherein the pivot tube extends through alower detent of the powerfold actuator, an output gear of the powerfoldactuator, an upper detent of the powerfold actuator, and a housing ofthe powerfold actuator, the housing comprising an upper housing portionand a lower housing portion; wherein the powerfold actuator comprises abiasing element disposed between the upper housing portion and an upperend of the pivot tube, the biasing element releasably retains thepowerfold actuator in at least one detent state of the powerfoldactuator; wherein the mirror head is attached at the housing of thepowerfold actuator, and wherein the mirror head and the housing of thepowerfold actuator, when the powerfold actuator is electricallyoperated, move together and in tandem about a pivot axis of the pivottube of the powerfold actuator; wherein the powerfold actuator comprisestwo electrically powered motors disposed in the housing, and wherein thetwo electrically powered motors, when electrically powered, rotatablydrive respective gears that engage the output gear to impart movement ofthe housing and the mirror head relative to the output gear; wherein thetwo electrically powered motors are oriented with respective outputshafts of the two electrically powered motors parallel to the pivot axisof the pivot tube; wherein, when the mirror head is moved from theextended position toward the folded position, the housing of thepowerfold actuator and the mirror head move axially along the pivot axisof the pivot tube away from the mounting base and the base portion ofthe powerfold actuator; wherein the upper detent is disposed radiallyoutboard of the pivot tube and radially inboard of the output gear andthe lower detent, and wherein the upper detent includes a detent lipthat engages an upper detent surface of the lower detent; wherein theupper detent is axially movable along the pivot axis of the pivot tubeand non-rotatably engaged with the base portion; wherein the output gearis non-rotatably engaged with the lower detent and is axially movablealong the pivot axis of the pivot tube; wherein the at least one detentstate of the powerfold actuator comprises (i) a primary detent state and(ii) a secondary detent state; wherein the primary detent state isengaged to maintain the mirror head at the extended position when themirror head is moved via the powerfold actuator to the extendedposition; wherein, when the powerfold actuator is in the primary detentstate, a spring load path of the biasing element is through the outputgear and the lower detent to the base portion; wherein, when thepowerfold actuator is in the secondary detent state, the spring loadpath of the biasing element is through the detent lip of the upperdetent and the lower detent to the base portion; wherein, when themirror head is manually moved, the output gear and the housing movetogether relative to the base portion; and wherein, with the mirror headin the folded position, and when the mirror head is manually moved fromthe folded position to the extended position, the primary detent stateis disengaged and the secondary detent state is engaged to releasablyretain the mirror head at the extended position.
 14. The exteriorrearview mirror assembly of claim 13, wherein the detent lip of theupper detent has a lower detent surface that engages the upper detentsurface of the lower detent, and wherein the detent lip includes anupper detent surface that engages an inner detent surface of the upperhousing portion.
 15. The exterior rearview mirror assembly of claim 14,wherein, when the powerfold actuator is in the primary detent state, theupper detent surface of the detent lip of the upper detent does notengage the inner detent surface of the upper housing portion.
 16. Theexterior rearview mirror assembly of claim 14, wherein, when thepowerfold actuator is in the secondary detent state, the upper detentsurface of the lower detent urges the upper detent upward against theinner detent surface of the upper housing portion.
 17. The exteriorrearview mirror assembly of claim 13, wherein, when the mirror head ismanually moved, the housing and the output gear move axially along thepivot axis of the pivot tube relative to the base portion and the upperdetent moves axially along the pivot axis of the pivot tube relative tothe lower detent.
 18. The exterior rearview mirror assembly of claim 13,wherein the biasing element applies a force at the upper housing fromthe upper end of the pivot tube.
 19. An exterior rearview mirrorassembly for a vehicle, the exterior rearview mirror assemblycomprising: a mirror head comprising a mirror reflective element; amounting base configured for attachment at a side of a vehicle; whereinthe mirror head is movable relative to the mounting base between atleast an extended position, where the mirror head is extended outwardfrom the side of the vehicle so that the mirror reflective element ispositioned to provide a rearward view at the side of the vehicle to adriver of the vehicle, and a folded position, where the mirror head ismoved inward from the extended position toward the side of the vehicle;a seal disposed between the mirror head and the mounting base; apowerfold actuator electrically operated to move the mirror headrelative to the mounting base between the folded position and theextended position; wherein the powerfold actuator comprises a baseportion that attaches at the mounting base and a pivot tube extendingfrom the base portion, and wherein the pivot tube extends through alower detent of the powerfold actuator, an output gear of the powerfoldactuator, an upper detent of the powerfold actuator, and a housing ofthe powerfold actuator, the housing comprising an upper housing portionand a lower housing portion; wherein the powerfold actuator comprises abiasing element disposed between the upper housing portion and an upperend of the pivot tube, the biasing element releasably retains thepowerfold actuator in at least one detent state of the powerfoldactuator; wherein the mirror head is attached at the housing of thepowerfold actuator, and wherein the mirror head and the housing of thepowerfold actuator, when the powerfold actuator is electricallyoperated, move together and in tandem about a pivot axis of the pivottube of the powerfold actuator; wherein, when the mirror head is movedfrom the extended position toward the folded position, the housing ofthe powerfold actuator and the mirror head move axially along the pivotaxis of the pivot tube away from the mounting base and the base portionof the powerfold actuator to reduce pressure at the seal; wherein thepowerfold actuator comprises at least one electrically powered motordisposed in the housing, and wherein the at least one electricallypowered motor, when electrically powered, rotatably drives a gear thatengages the output gear to impart movement of the housing and the mirrorhead relative to the output gear; wherein the upper detent is disposedradially outboard of the pivot tube and radially inboard of the outputgear and the lower detent, and wherein the upper detent includes adetent lip that engages an upper detent surface of the lower detent;wherein the detent lip of the upper detent has a lower detent surfacethat engages the upper detent surface of the lower detent, and whereinthe detent lip includes an upper detent surface that engages an innerdetent surface of the upper housing portion; wherein the upper detent isaxially movable along the pivot axis of the pivot tube and non-rotatablyengaged with the base portion; wherein the output gear is non-rotatablyengaged with the lower detent and is axially movable along the pivotaxis of the pivot tube; wherein the at least one detent state of thepowerfold actuator comprises (i) a primary detent state and (ii) asecondary detent state; wherein the primary detent state is engaged tomaintain the mirror head at the extended position when the mirror headis moved via the powerfold actuator to the extended position; wherein,when the powerfold actuator is in the primary detent state, a springload path of the biasing element is through the output gear and thelower detent to the base portion; wherein, when the powerfold actuatoris in the secondary detent state, the spring load path of the biasingelement is through the detent lip of the upper detent and the lowerdetent to the base portion; wherein, when the mirror head is manuallymoved, the output gear and the housing move together relative to thebase portion; and wherein, with the mirror head in the folded position,and when the mirror head is manually moved from the folded position tothe extended position, the primary detent state is disengaged and thesecondary detent state is engaged to releasably retain the mirror headat the extended position.
 20. The exterior rearview mirror assembly ofclaim 19, wherein, when the powerfold actuator is in the primary detentstate, the upper detent surface of the detent lip of the upper detentdoes not engage the inner detent surface of the upper housing portion.21. The exterior rearview mirror assembly of claim 19, wherein, when thepowerfold actuator is in the secondary detent state, the upper detentsurface of the lower detent urges the upper detent upward against theinner detent surface of the upper housing portion.
 22. The exteriorrearview mirror assembly of claim 19, wherein, when the mirror head ismanually moved, the housing and the output gear move axially along thepivot axis of the pivot tube relative to the base portion and the upperdetent moves axially along the pivot axis of the pivot tube relative tothe lower detent.
 23. The exterior rearview mirror assembly of claim 19,wherein the at least one electrically powered motor is oriented with anoutput shaft of the at least one electrically powered motor parallel tothe pivot axis of the pivot tube.
 24. The exterior rearview mirrorassembly of claim 19, wherein the biasing element applies a force at theupper housing from the upper end of the pivot tube.